Nonradiative energy transfer between two different activator sites in La(4-x)Ca(x)Si12O(3+x)N(18-x):Eu2+.

ABSTRACT

Energy transfer, which affects the entire performance of luminescent material, has been generally treated as an averaged parameter by assuming the host material to be a homogeneous continuum. However, energy transfer should be investigated in association with the crystallographic local structure around an activator site. To accomplish this, we established an analytical model and derived comprehensive rate equations, elucidating the relationship between the local structure and energy transfer behavior of La(4-x)Ca(x)Si12O(3+x)N(18-x)Eu2+, which is a recently discovered luminescent material for use in light-emitting diodes. Using the rate-equation model with the assistance of particle swarm optimization, the full-scale decay curves of donors and acceptors located at different crystallographic sites was computed.